System for waste heat recovery for a fluid heater

ABSTRACT

A fluid heating apparatus has a fluid inlet, a fluid outlet, and a fluid path, and comprises a fluid pumping assembly configured to increase the pressure of the fluid on the fluid path, and forms a portion of the fluid path. A heating assembly is configured to heat the fluid between the fluid inlet and outlet, and forms a portion of the fluid path. A heat recovery assembly is configured to recover heat from the exhaust gases, and forms a portion of the fluid path to transfer recovered heat to fluid moving through the fluid path. A collection assembly may be employed to collect condensation from exhaust gases passing through the recovery assembly. A method is also disclosed.

BACKGROUND

1. Field

The present disclosure relates to fluid heating apparatus and moreparticularly pertains to a new system for waste heat recovery for afluid heater for capturing a portion of the heat exhausted from theapparatus that would otherwise be lost to the environment duringoperation, as well as providing the ability to capture vapor andparticulate matter in the gases.

2. Description of the Prior Art

A fluid heating apparatus is utilized to increase the temperature of afluid at the outlet of the apparatus, and may also include a pump toincrease the pressure of the fluid at the outlet. In some types of thefluid heater apparatus, a fuel is burned to generate the heat necessaryto warm the fluid. The exhaust gases from the combustion leave theheating assembly of the apparatus and are vented to the environment.

SUMMARY

In view of the foregoing, the present disclosure describes a new systemfor waste heat recovery for a fluid heater which may be utilized tocapture a portion of the heat exhausted from the apparatus that wouldotherwise be lost to the environment during operation.

In one aspect, the present disclosure relates to a fluid heatingapparatus having a fluid inlet, a fluid outlet, and a fluid pathextending between the fluid inlet and fluid outlet. The apparatuscomprises a fluid pumping assembly configured to increase a pressurecharacteristic of the fluid between the fluid inlet and fluid outlet.The fluid pumping assembly forms a portion of the fluid path to increasethe pressure of fluid moving along the fluid path. The apparatus furtherincludes a heating assembly configured to heat the fluid between thefluid inlet and the fluid outlet, and the heating assembly also forms aportion of the fluid path to increase a temperature of the fluid movingalong the fluid path. The apparatus also includes a heat recoveryassembly configured to recover heat from the exhaust gases. The heatrecovery assembly forms a portion of the fluid path to transferrecovered heat to fluid moving through the fluid path.

In another aspect, the present disclosure relates to a fluid heatingapparatus having a fluid inlet, a fluid outlet, and a fluid pathextending between the fluid inlet and fluid outlet, and the apparatuscomprises a fluid pumping assembly configured to increase a pressurecharacteristic of the fluid between the fluid inlet and fluid outlet.The fluid pumping assembly forms a portion of the fluid path to increasethe pressure of fluid moving along the fluid path. The apparatus furtherincludes a heating assembly configured to heat the fluid between thefluid inlet and the fluid outlet, and the heating assembly forms aportion of the fluid path to increase a temperature of the fluid movingalong the fluid path. The apparatus also includes a condensationcollection assembly configured to collect condensation from exhaustgases produced by the heating assembly. Particulate matter is collectedwith the collection of the condensed fluid from the exhaust gases.

In still another aspect, the disclosure relates a method of recoveringheat from a fluid heater. The method includes providing a fluid heaterdefining a fluid path between a fluid inlet and a fluid outlet for thefluid heater, with the fluid heater having a heating assembly and apumping assembly. The method further includes receiving a flow of fluidat the fluid inlet of the fluid path of the fluid heater, with the fluidflow being at a first pressure at the fluid inlet. The method alsoincludes preheating the fluid flow by transferring heat from exhaustgases produced by the heating assembly to the fluid flow moving alongthe fluid path, the exhaust gases being generated by a heating chamberof the heating assembly. The method still further includes raising thepressure of the fluid flow moving along the fluid path from the firstpressure to a second pressure after the preheating of the fluid flow,with the second pressure being higher than the first pressure. Themethod includes heating the fluid flow moving along the fluid path atthe second pressure by passing the fluid flow through the heatingchamber of the heating assembly.

There has thus been outlined, rather broadly, some of the more importantelements of the disclosure in order that the detailed descriptionthereof that follows may be better understood, and in order that thepresent contribution to the art may be better appreciated. There areadditional elements of the disclosure that will be described hereinafterand which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment orimplementation in greater detail, it is to be understood that the scopeof the disclosure is not limited in its application to the details ofconstruction and to the arrangements of the components set forth in thefollowing description or illustrated in the drawings. The disclosure iscapable of other embodiments and implementations and is thus capable ofbeing practiced and carried out in various ways. Also, it is to beunderstood that the phraseology and terminology employed herein are forthe purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present disclosure. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present disclosure.

The advantages of the various embodiments of the present disclosure,along with the various features of novelty that characterize thedisclosure, are disclosed in the following descriptive matter andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be better understood and when consideration is givento the drawings and the detailed description which follows. Suchdescription makes reference to the annexed drawings wherein:

FIG. 1 is a schematic perspective view of a new system for waste heatrecovery for a fluid heater according to the present disclosure.

FIG. 2 is a schematic exploded perspective view of the system, accordingto an illustrative embodiment.

FIG. 3A is a schematic perspective view of the heat recovery assembly ofthe system, according to an illustrative embodiment.

FIG. 3B is a schematic exploded view of the heat recovery assembly ofthe system shown in FIG. 3A.

FIG. 4 is a schematic sectional view of the heating assembly and heatrecovery assembly, according to an illustrative embodiment.

FIG. 5 is a schematic diagram of the system, according to anillustrative embodiment employing a single heat exchanger.

FIG. 6 is a schematic diagram of the system, according to anillustrative embodiment employing multiple heat exchangers with thefluid path passing through the exchangers in parallel.

FIG. 7 is a schematic diagram of the system, according to anillustrative embodiment employing multiple heat exchangers with thefluid path passing through the exchangers in series.

FIG. 8 is a schematic diagram of the system, according to anillustrative embodiment employing a single heat exchanger without afluid accumulating tank in which condensation is not introduced into thefluid flow along the fluid path.

FIG. 9 is a schematic flow diagram of a method of the system accordingto an illustrative implementation.

FIG. 10 is a schematic perspective view of a fluid heating apparatusmounted on a skid and employing a gasoline engine for the pumpingassembly, with the heating chamber of the heating assembly beingvertically oriented.

FIG. 11 is a schematic perspective view of a fluid heating apparatusmounted on a skid and employing a gasoline engine for the pumpingassembly, with the heating chamber of the heating assembly beinghorizontally oriented.

FIG. 12 is a schematic perspective view of a fluid heating apparatusconfigured for generally stationary use.

DETAILED DESCRIPTION

With reference now to the drawings, and in particular to FIGS. 1 through12 thereof, a new system for waste heat recovery for a fluid heaterembodying the principles and concepts of the disclosed subject matterwill be described.

The disclosure relates a number of innovations that may relate to avariety of apparatus, but are particularly useful on a fluid heatingapparatus 10 that heats a flow of fluid moving along a fluid path 12extending through the apparatus 10 between a fluid inlet 14 and a fluidoutlet 16, so that the temperature of the fluid exiting the fluid outletis greater than the temperature of the fluid entering the fluid inlet.The fluid heating apparatus 10 may also increase a pressure of the fluidbetween the fluid inlet 14 and the fluid outlet 16, so that the fluidexiting the fluid outlet has a greater pressure than fluid entering thefluid inlet. In some implementations, the fluid heating apparatus 10 isutilized to wash objects using the hot fluid exiting the fluid outlet athigh pressure, which can produce steam when the heated high pressurewater is exposed to the atmosphere. Typically, but not necessarily, thefluid is a liquid and the liquid is water. The water at the inlet 14 maybe at ambient temperature and a pressure that is supplied by a municipalwater supply, and the water at the outlet 16 may have a significantlyhigher temperature and pressure. The fluid heating apparatus 10 may alsobe implemented on a portable platform, and will be illustrativelydescribed herein as a portable unit, although the benefits of thedisclosure are not limited to a portable unit and may be employed, forexample, on a stationary or relatively stationary unit. For example, theapparatus 10 may be implemented on a trailer to provide portability, ora skid that may be picked up and transported between locations.

In greater detail, the fluid heating apparatus 10 may include a frame 18with a front 20 and a rear 22, and laterally-opposite first 24 andsecond 26 sides. The frame 18 may comprise various portions, including amain frame portion 28 and a handle frame portion 30, as well as alinking frame portion 32. The main frame portion 28 may extend from thefront 20 of the frame to the rear 22, and may include a first sidestructure 34 and a second side structure 36. Each of the side structures34, 36 may have a front end and a rear end that generally correspond inlocation to the front 20 and rear 22 of the frame, respectively. Thelinking frame portion 32 may link the first 34 and second 36 sidestructures of the main frame portion to support various elements of theapparatus 10. The linking frame portion 32 may include a front portionlocated at the front of the frame and a rear portion located at the rearof the frame. The handle frame portion 30 may provide a handle orhandhold for a user to move the apparatus around. The handle frameportion 30 may extend upwardly from a location between the front 20 andrear 22 of the frame 18, and may then extend rearwardly to the rear 22.A section of the handle frame portion may extend transversely betweenthe sides 24, 26 of the frame, and the section may form a handle to begripped by the user. The frame described herein is merely illustrativeof the variety of frames that may be employed, and therefore theapparatus 10 is not limited to any particular frame configuration.

The apparatus 10 may also include a plurality of wheels mounted on theframe 18 for permitting the frame and the supported elements of theapparatus 10 to move across a floor or ground surface. The plurality ofwheels may include a pair of front wheels 38 mounted on the frame towardthe front 20 of the frame and a pair of rear wheels 39 mounted on theframe toward the rear 22. Each of the front wheels 38 may be mounted forswivel movement with respect to the frame 18, so that each of the wheels38 is free to rotate about a substantially vertical axis. Each frontwheel 38 may also be free to rotate independently of the other frontwheel. Each of the front wheels 38 may be mounted on the front end ofone of the side structures of the main frame portion 28, although otherpositionings may be employed. In some embodiments, each front wheel 38has a diameter and each rear wheel 39 has a diameter, and the diameterof the front wheels is substantially the same as the diameter of therear wheels. The rear wheels 39 may be mounted on a common axle. Asnoted above, the apparatus may optionally be configured without wheelsand may employ a skid to some type of more stationary mounting.

A fluid accumulating tank 40 may be included in the apparatus 10 foraccumulating fluid in the fluid path 12, although the presence of anaccumulating tank 40 is not critical to the function of the apparatus.The fluid accumulating tank 40 may thus be in fluid communication withthe fluid path 12, and an interior of the tank may form a portion of thefluid path. The tank 40 may function as an enlargement of the fluid pathfor accommodating an extra quantity of fluid so that the remainder ofthe fluid path between the tank 40 and the fluid outlet 16 is providedwith a supply of fluid even if a main fluid supply is subject topressure and flow rate variations. The tank 40 may have an auxiliaryinlet 42 for an auxiliary flow of fluid described below. The fluidaccumulating tank 40 may have an accumulating tank outlet 44. The fluidaccumulating tank 40 may be mounted on one of the sides 24, 26 of theframe, such as the first side 24. The accumulating tank 40 may belocated at least partially between the front 38 and the rear 39 wheelson the first side 24 of the frame. The accumulating tank 40 may extendover the rear wheel 39 on the first side, and may also extend at leastpartially over the front wheel 38.

The fluid heater apparatus 10 may also include a fluid pumping assembly46 that is configured to increase a pressure characteristic of the fluidbetween the fluid inlet 14 and fluid outlet 16. The fluid pumpingassembly 46 may be a mechanical pump and may be operated by any means,such as electricity or gas engine. The fluid pumping assembly 46 may bein fluid communication with, and form a portion of, the fluid path 12.In some embodiments, the fluid pumping assembly 46 is in fluidcommunication with the accumulating tank outlet 44 to draw fluid fromthe interior of the tank 40. The fluid pumping assembly 46 may thusincrease a pressure of the fluid from a first, relatively lower pressureof the fluid in the interior of the accumulating tank 40 and raise it toa second, relatively higher pressure leaving the fluid pumping assemblyat a pumping assembly outlet 48. The fluid pumping apparatus 46 maycomprise a fluid pump of any suitable type. The first pressure may be apressure that is available from a conventional water supply system, andthe second pressure may be a pressure that is utilized for high pressurewashing. Illustratively, the first pressure may be in the range of 0 psito approximately 200 psi, and in many applications the first pressuremay be in the range of 0 psi to approximately 120 psi. The secondpressure may range above approximately 500 psi.

A heating assembly 50 may be included in the heater apparatus 10 to heatthe fluid between the fluid inlet 14 and the fluid outlet 16, and mayform a portion of the fluid path 12 therebetween. The heating assembly50 may be in fluid communication with the pumping assembly 46 via thepumping assembly outlet 48. The heating assembly 50 may have a heatingassembly outlet 52, and the outlet 52 may form the fluid outlet 16 ofthe fluid heating apparatus 10. The heating assembly 50 may be mountedon the frame 18, and may be located toward the rear 22 of the frame,although this positioning is not critical to the apparatus 10.

In many embodiments of the apparatus 10, the heating assembly 50includes a heating chamber 54, which may have any of a variety ofdifferent configurations including a vertical orientation where theexhaust gases of combustion move generally vertically in the chamber, ora horizontal orientation where the exhaust gases move generallyhorizontally in the chamber. In some embodiments, the heating chamber 54has an interior 56, and a top 58 and a bottom 59. The heating chamber 54may have an exhaust opening 60 for exhaust gases to pass out of theinterior 54 of the heating chamber. The exhaust opening 60 may belocated on one side of the heating chamber, and in such embodiments theexhaust gases are not exhausted out of the top 58 of the chamber. Theexhaust opening 60 may be located below the top 58 of the heatingchamber, but may be located adjacent to the top. While the illustrativeheating chamber 54 is generally vertically oriented, it should berecognized that many of the features discussed herein may apply to aheating chamber having a generally horizontal orientation.

In greater detail, the illustrative heating chamber 54 may comprise aperimeter wall 62 that defines the interior 56 of the heating chamber.The exhaust opening 60 may be formed in the perimeter wall 62, and maybe located toward a top end 64 of the perimeter wall. The perimeter wall62 may be substantially cylindrical in shape, and may be centered abouta substantially vertical axis. The perimeter wall may incorporate aninsulating material to reduce the temperature of the outer surface ofthe perimeter wall relative to the temperature in the interior 56.

The heating chamber 54 may also include a top wall 66 that is mounted onthe perimeter wall 62 and that closes the top end 64 of the perimeterwall. The top wall 66 may be continuous between the extent of theperimeter wall to prevent exhaust gases from passing out of the interior56 of the heating chamber through the top end 64 of the perimeter wall.

The heating assembly 50 may further include a heat source such as aburner 68 or other combustion source that produces heated gases in theinterior 56 of the heating chamber. For example, the burner 68 may beconfigured to burn a liquid fuel such as oil or a gaseous fuel such asnatural gas or liquefied petroleum (LP) gas, as well as otherhydrocarbon-based fuels. The burner 68 may have a variety ofconfigurations, such as up-firing, side-firing, or down firing. In anillustrative embodiment, the burner 68 may be positioned toward thebottom 59 of the heating chamber 54, and may be oriented to direct aflame and the exhaust gases from the flame in a substantially upwarddirection in the interior of the heating chamber. The combustion of fuelby the burner produces water vapor in the exhaust gases that are alsoproduced by the combustion, as well as the water vapor that is presentin the ambient air drawn into the burner to support the combustion. Afluid circulating conduit 70 of the heating assembly 50 may bepositioned in the interior 56 of the heating chamber to circulate fluidin the fluid path in the exhaust gases produced by the burner. The fluidcirculating conduit 70 may thus form a portion of the fluid path 12, andmay be formed into a plurality of coils, although this configuration isnot critical.

The fluid heating apparatus 10 may also include a fuel tank 72 forholding a quantity of fuel to fuel the heating assembly 50, and morespecifically the burner 68. The use of a fuel tank is not critical tothe apparatus, and may be omitted in some configurations, such as thosein which a gaseous fuel is utilized. The fuel tank 72 is in fluidcommunication with the burner 68 to provide the burner with fuel fromthe tank 72. The fuel tank 72 may be mounted on the frame 16, and may belocated on one side of the frame such as on the second side 26 of theframe opposite of the fluid accumulating tank 40 that may be located onthe first side 24 of the frame. The fuel tank 72 may be located at leastpartially between the front 38 and the rear 39 wheels on the second sideof the frame. The fuel tank 72 may extend over the rear wheel 39 on thesecond side, and may also extend at least partially over the front wheel38.

Significantly, the apparatus 10 includes a heat recovery assembly 74that is configured to recover heat from the exhaust gases. The recoveryof the heat from the exhaust gases may or may not occur after theexhaust gases have left or passed out of the interior of the heatingassembly 50. The heat recovery assembly 74 may be configured such thatexhaust gases emanating from the heating chamber pass through aninterior 76 of the heat recovery assembly, where heat exchanging meansare positioned to transfer the heat contained in the exhaust gases toanother medium, such as fluid moving along the fluid path 12. The heatrecovery assembly 74 is primarily and substantially located outside ofthe heating assembly 50, although there may be some connection of therecovery assembly 74 to the heating assembly 50 for the purposes of, forexample, guiding the exhaust gases from the heating assembly to therecovery assembly.

The transfer of heat to the fluid in the fluid path 12 may occur beforethe pressure of the fluid has been increased, such as by the pumpingassembly 46. Thus, in such embodiments, the heat recovery assembly 74acts to pre-heat the fluid in the fluid path prior to the fluid beingpumping to a higher pressure, and the heat recovery assembly 74 may haveor form the fluid inlet 14 for receiving fluid into the fluid heatingapparatus 10. This is in contrast to the fluid moving through theheating assembly 50, the pressure of which has been raised by thepumping assembly 46 or other suitable means. Significantly, the elementsof the heat recovery assembly 74 are not subjected to the higherpressures that are present in the fluid flow moving through the heatingassembly 50 and out of the fluid outlet 16 of the apparatus, and as aresult, elements of less sturdy and bulky character may be utilized inthe heat recovery assembly to decrease manufacturing costs and increasethe transfer of heat.

The heat recovery assembly 74 may have an exhaust gas intake 78 forreceiving exhaust gas into the assembly 74 and an exhaust gas outlet 80for expelling the exhaust gas from the assembly 74. The exhaust gasinlet 78 may receive exhaust gases from the heating assembly 50, andthose gases may then be passed out of the interior 76 of the heatrecovery assembly through the outlet 80.

In greater detail, the heat recovery assembly 74 may comprise a housing82 although the use of a housing is not critical to the apparatus. Thehousing 82 may be mounted on the heating assembly 50, although otherpositions and relationships to the heating assembly may be utilized. Thehousing 82 may define the interior 76 (or a portion thereof) of the heatrecovery assembly 74. In the illustrative embodiments, the housingincludes a first wall 84 and a second wall 86. The first wall 84 mayinclude a receiving opening 88, which in some embodiments may form theexhaust gas intake 78 of the heat recovery assembly 74, while in otherembodiments structure may be interposed between the housing and theperimeter wall 62 of the heating assembly 50. The second wall 86 may bepositioned opposite of the first wall on the housing, and may include atleast one aperture for permitting exhaust gases in the interior of thehousing to exit the interior. The aperture or apertures may form theexhaust gas outlet 80 for the recovery assembly 74. The second wall 86may be oriented substantially parallel to the first wall, although thisis not critical.

The housing 82 may also include side walls 90 that extend between thefirst 84 and second 86 walls to form a perimeter about the interior 76of the housing. The side walls 90 may include a top side wall 92, afirst side wall 94, a second side wall 96, and a bottom side wall 98,which may form a substantially rectangular perimeter, although otherperimeter shapes may be employed.

An exhaust guide may be employed to guide exhaust gases from the heatingassembly 50 to the heat recovery assembly 74. Illustratively, theexhaust guide may comprise a duct 100 forming a passage for the exhaustgases between the heating chamber 54 and the housing 82. The duct 100may be connected to the perimeter wall 62 of the heating chamber 54 andthe first wall 84 of the housing, with the passage of the duct 100 beingin fluid or gaseous communication with the exhaust opening 60 of theheating chamber and the receiving opening 88 of the housing 82. The useof the exhaust guide allows for a degree of separation between thehousing 82 of the heat recovery assembly 74 and the heating chamber 54,and facilitates an orientation of the housing 82 of the heat recoveryassembly 74.

The heat recovery assembly 74 may further include at least one heatexchanger 102, which may be positioned in the interior 76 of the housing82. In the illustrative embodiments, a pair of heat exchangers 102, 104is employed in the assembly 74, although one or more than two exchangersmay be used. The heat exchangers may comprise air to liquid heatexchangers, so that heat from the exhaust gases passing over the heatexchangers is transferred to the fluid or liquid moving through thefluid path. For example, each of the heat exchangers may comprise aconduit through which the fluid on the fluid path passes, and finsmounted on the conduit that draw heat from the gases passing over themand transfer the heat to the conduit (and in turn the fluid passingthrough the conduit). The heat exchangers are not limited to thisconfiguration, although this configuration has been found to be highlysuitable for the purposes of the apparatus 10. More specifically, theinclusion of fins on the heat exchangers, while beneficial, is notrequired,

In embodiments in which multiple heat exchangers are utilized, the heatexchangers 102, 104 may be configured to encounter the flow of exhaustgases in parallel with respect to each other, although two or moreexchangers may be oriented in a serial arrangement to the exhaust flowsuch that the exhaust flow encounters each of the exchangers one afteranother. In embodiments in which multiple heat exchangers are employed,the heat exchangers may be positioned in substantially the same plane sothat parallel air flows through the exchangers may be used. Otherconfiguration of the multiple heat exchangers may be employed, such aswhere the planes of the heat exchangers are angled with respect to eachother. For example, the planes of the heat exchangers may be in avertically-inclined arrangement that forms an inverted V shape such thatupper end of the exchangers are closer to each other and the lower endsare further apart. The flow of the exhaust gases passing through theexchangers may separate into to divergent flows. Other arrangementgeometries for multiple heat exchangers may also be used.

In the illustrative embodiment, the fluid path 12 passes through the oneor more heat exchangers in series, so that the fluid moving along thepath 12 passes through all of the exchangers. Optionally, the fluid pathmay move through multiple heat exchangers in parallel. This parallelflow may be accomplished by dividing the fluid flow downstream from(after) the fluid inlet 14, but upstream (before) the fluid pathencounters the exchangers. The fluid flow may be rejoined downstreamfrom the heat exchangers. It should be recognized that the fluid path 12could pass through multiple exchangers in both series and parallelarrangements. Also, a plurality of heat exchangers may include up tofour or more heat exchangers. While a heat exchanger with a generallyplanar configuration is depicted, it is contemplated that heatexchangers with other configurations may be employed, such those havingcylindrical and even domed shapes as well as other shapes.

A support bracket 106 may be implemented in the housing on which theexchangers are mounted, and the support bracket may be utilized to spaceor separate the heat exchangers from the first wall 84 so that the flowof exhaust gases is able to reach a greater area of the exchangers evenwhen a smaller receiving opening 88 is formed in the first wall. Thebracket 106 may also serve to support the exchangers in a spacedrelationship with the second wall 86.

A significant feature of the heat recovery assembly 74 is the optionalorientation of the heat exchanger or exchangers of the assembly 74,although the orientation of the exchanger is not a critical feature ofthe recovery assembly. The exchangers extend in a major plane, which isgenerally oriented perpendicularly to the plane of the fins of theexchanger, and the major plane may be inclined from a verticalorientation so that the major plane is not vertically oriented and isnot horizontally oriented. The major plane of the exchangers may beinclined or tilted at angles between 0 and approximately 90 degrees(inclusive), and in some embodiments an angle of approximately 5 degreesto approximately 45 degrees from a vertical plane. In this inclinedorientation, the plane of the fins of the heat exchanger may bevertically oriented. One advantage of the inclined orientation is thatdripping of the condensation on the fins from the fins is facilitated,as the edges of the fins are also inclined and do not present ahorizontal edge.

Another significant optional feature of the apparatus 10 is thecapability to recover heated condensation from heat exchangers, so thatthe collected condensation may optionally be introduced into the fluidflow in the fluid path, although the collected condensation may bedisposed of in other ways, such as by, for example, draining thecondensation to the ground or collection in a separate tank for periodicdisposal. Advantageously, the collection of condensed water from theexhaust gases may also function to collect particulate matter from theexhaust gases as the particulate matter collects on the heat exchangerwith the condensed vapor, and thus may provide a partial “scrubbing”function on the exhaust gases.

To reintroduce the collected condensation into the fluid flow, theillustrative embodiments of the apparatus 10 include a condensationcollection assembly 108 which employs a drain 110 in the bottom of thehousing 82 to drain condensation that drips from the heat exchangersinto the interior of the housing of the heat recovery assembly 74. Theliquefied condensation collects in the bottom of the interior of thehousing, and is able to drain from the interior through a drain conduit112. The drain conduit 112 is in fluid communication with the fluid path12, such as in communication with the auxiliary inlet 42 of theaccumulating tank 40, where the condensation liquid is able to mix withthe fluid that has entered through the fluid inlet 14.

Another aspect of the disclosure relates to a method of recovering heatfrom a fluid heater, such as from the exhaust gases emanating from theheater assembly that is exhausted to the environment. The method mayinclude providing a fluid heater that defines a fluid path between afluid inlet and a fluid outlet for the fluid heater. The fluid heatermay have a heating assembly and a pumping assembly, as well as otherelements described herein. The method may also include receiving a flowof fluid at the fluid inlet of the fluid path of the fluid heater, andthe fluid flow may be at a first pressure and a first temperature at thefluid inlet. The method may also include preheating the fluid flow bytransferring heat from exhaust gases produced by the heating assembly tothe fluid flow moving along the fluid path, and the exhaust gases mayhave passed out of the heating chamber of the heating assembly. The stepof transferring heat may include passing the fluid flow moving along thefluid path through a stream of the exhaust gases emanating from theheating assembly. The step of transferring heat may include passing thefluid flow through one or more heat exchangers that form a portion ofthe fluid path and that are exposed to the stream of exhaust gases fromthe heating assembly. The preheating of the fluid flow may occur outsideof the heating chamber of the heating assembly, although it may alsooccur inside the heating chamber.

The method may also include raising the pressure of the fluid flowmoving along the fluid path from the first pressure to a second pressureafter the preheating has been performed on the fluid flow. The secondpressure is higher than the first pressure. The method may also includeheating the fluid flow moving along the fluid path at the secondpressure by passing the fluid flow through the heating chamber of theheating assembly. The majority of the temperature increase in the fluidflow occurs in the heating chamber when compared to the preheating ofthe fluid flow prior to raising the pressure of the fluid flow.

Another aspect of the method may be collecting vaporized fluid from theexhaust gases, condensing that vapor into a liquid, and adding thatcondensed liquid to the fluid flow. In some implementations, vaporizedwater in contained in the exhaust gases due to the combustion of thefuel, and the vaporized water condenses on a heat exchanger that has therelatively cooler fluid flow moving through it. For example, the watermay condense on the surfaces of the heat exchanger, such as on the finsof the heat exchanger. As the fluid accumulates on the fins, the fluidmay tend to drip from the fins, and the condensation is collected anddirected to the fluid flow, such as into the fluid accumulating tank.

With respect to the above description then, it is to be realized thatthe optimum dimensional relationships for the parts of the disclosedembodiments and implementations, to include variations in size,materials, shape, form, function and manner of operation, assembly anduse, are deemed readily apparent and obvious to one skilled in the artin light of the foregoing disclosure, and all equivalent relationshipsto those illustrated in the drawings and described in the specificationare intended to be encompassed by the present disclosure.

Therefore, the foregoing is considered as illustrative only of theprinciples of the disclosure. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the disclosed subject matter to the exact constructionand operation shown and described, and accordingly, all suitablemodifications and equivalents may be resorted to that fall within thescope of the claims.

I claim:
 1. A fluid heating apparatus having a fluid inlet, a fluidoutlet, and a fluid path extending between the fluid inlet and fluidoutlet, the apparatus comprising: a fluid pumping assembly configured toincrease a pressure characteristic of the fluid between the fluid inletand fluid outlet, the fluid pumping assembly forming a portion of thefluid path to increase the pressure of fluid moving along the fluidpath; a heating assembly configured to heat the fluid between the fluidinlet and the fluid outlet, the heating assembly forming a portion ofthe fluid path to increase a temperature of the fluid moving along thefluid path; and a heat recovery assembly configured to recover heat fromthe exhaust gases, the heat recovery assembly forming a portion of thefluid path to transfer recovered heat to fluid moving through the fluidpath.
 2. The apparatus of claim 1 wherein the heat recovery assembly isconfigured to heat fluid on the fluid path prior to the fluid passingthrough the heating assembly.
 3. The apparatus of claim 1 wherein theheat recovery assembly is configured to heat fluid on the fluid pathprior to the fluid path passing through the fluid pumping assembly. 4.The apparatus of claim 1 wherein the heat recovery assembly includes aplurality of heat exchangers.
 5. The apparatus of claim 4 wherein thefluid path passes through the plurality of heat exchangers in a seriesarrangement.
 6. The apparatus of claim 4 wherein exhaust gases from theheating assembly pass through the pair of heat exchangers of the heatrecovery assembly in parallel.
 7. The apparatus of claim 1 additionallycomprising a fluid accumulating tank in fluid communication with thefluid path; and wherein the fluid path passes through the heat recoveryassembly prior to passing through the fluid accumulating tank.
 8. Theapparatus of claim 1 additionally comprising a fluid accumulating tankin fluid communication with the fluid path; wherein the heat recoveryassembly is configured to heat fluid on the fluid path prior to thefluid passing through the heating assembly; wherein the heat recoveryassembly is configured to heat fluid on the fluid path prior to thefluid path passing through the fluid pumping assembly; wherein the heatrecovery assembly has an exhaust gas intake and an exhaust gas outlet,the heat recovery assembly being configured such that exhaust gasesemanating from the heating assembly pass through an interior of the heatrecovery assembly, at least one heat exchanger being positioned in theinterior of the heat recovery assembly; wherein the fluid path passesthrough the heat recovery assembly prior to passing through the fluidaccumulating tank; wherein the heat recovery assembly includes acondensation collection assembly configured to collect condensation fromthe exhaust gases on a heat exchanger of the recovery assembly; whereinthe condensation collection assembly directs condensed fluid collectedfrom the exhaust gases into the fluid path; wherein the condensed fluidfrom the exhaust gases is directed to the fluid accumulating tank. 9.The apparatus of claim 1 wherein the heat recovery assembly includes acondensation collection assembly configured to collect condensation on aheat exchanger of the recovery assembly.
 10. The apparatus of claim 1wherein the condensation collection assembly directs condensed fluidcollected into the fluid path.
 11. The apparatus of claim 10additionally comprising a fluid accumulating tank in fluid communicationwith the fluid path; and wherein the condensed fluid is directed to thefluid accumulating tank.
 12. The apparatus of claim 9 wherein thecondensation collection assembly further collects particulate matter inthe collected condensation.
 13. A fluid heating apparatus having a fluidinlet, a fluid outlet, and a fluid path extending between the fluidinlet and fluid outlet, the apparatus comprising: a fluid pumpingassembly configured to increase a pressure characteristic of the fluidbetween the fluid inlet and fluid outlet, the fluid pumping assemblyforming a portion of the fluid path to increase the pressure of fluidmoving along the fluid path; a heating assembly configured to heat thefluid between the fluid inlet and the fluid outlet, the heating assemblyforming a portion of the fluid path to increase a temperature of thefluid moving along the fluid path; and a condensation collectionassembly configured to collect condensation from exhaust gases producedby the heating assembly; wherein particulate matter is collected withthe collection of the condensed fluid from the exhaust gases.
 14. Theapparatus of claim 13 wherein the condensed fluid collected from theexhaust gases is directed into the fluid path.
 15. The apparatus ofclaim 13 additionally comprising a heat recovery assembly configured torecover heat from the exhaust gases after the exhaust gases have leftthe heating assembly, the heat recovery assembly forming a portion ofthe fluid path to transfer recovered heat to fluid moving through thefluid path, the heat recovery assembly including at least one heatexchanger; and wherein the condensation collection assembly isconfigured to collect condensation on a heat exchanger of the heatrecovery assembly.
 16. A method of recovering heat from a fluid heater,comprising: providing a fluid heater defining a fluid path between afluid inlet and a fluid outlet for the fluid heater, the fluid heaterhaving a heating assembly and a pumping assembly; receiving a flow offluid at the fluid inlet of the fluid path of the fluid heater, thefluid flow being at a first pressure at the fluid inlet; preheating thefluid flow by transferring heat from exhaust gases produced by theheating assembly to the fluid flow moving along the fluid path, theexhaust gases being generated by a heating chamber of the heatingassembly; raising the pressure of the fluid flow moving along the fluidpath from the first pressure to a second pressure after the preheatingof the fluid flow, the second pressure being higher than the firstpressure; and heating the fluid flow moving along the fluid path at thesecond pressure by passing the fluid flow through the heating chamber ofthe heating assembly.
 17. The method of claim 16 additionally comprisingadding the condensed liquid to the fluid flow along the fluid path.